When a high voltage is applied to two electrodes, and when the two electrodes are moved to each other gradually, and when a given spacing between the two electrodes is reached, the so-called arc discharge will occur. Arc discharge is similar to the lightning generated by thunderclouds. In contrast to the momentariness of lightning, the electric sparks between two electrodes can persist for a long time and result in heat accumulation.
In electronic circuits, arc discharge usually causes the malfunction or damage of electronic elements, or even a fire, which may endanger life. In the traditional high-voltage loads, such as CCFL (Cold Cathode Fluorescent Lamp), EEFL (External Electrode Fluorescent Lamp), anion generators, cathode ray tubes, etc., arc discharge will occur between the load and the high-voltage power source because of the point discharge resulting from an imperfect contact, a humidity/temperature change or a broken/damaged circuit element. U.S. Pat. No. 6,940,234 and U.S. Pat. No. 6,867,955 disclosed a voltage detection mode to prevent from the arc discharge occurring in a high-voltage output section, wherein a voltage-conversion unit of an arc-discharge protection device receives a high-voltage arc-discharge signal from the high-voltage output section and converts the high-voltage arc-discharge signal into a low-voltage arc-discharge signal; a rectifier unit rectifies the low-voltage arc-discharge signal and outputs an arc-discharge noise; a trigger unit detects the arc-discharge noise and outputs a triggering signal to interrupt a control unit or a driving unit lest arc discharge result in heat accumulation on the peripheral elements, which causes a burnout or a fire. Besides, R.O.C. publication U.S. Pat. No. 591,976 and U.S. Pat. No. 591,839 disclosed arc-discharge protection devices with a current detection mode.
However, the abovementioned voltage detection mode and current detection mode need a complicated circuit, including the voltage conversion unit, the filter unit, the rectifier unit, etc., which increases the fabrication time and fabrication cost and lays a great burden on manufacturers and consumers.